The purpose of the six Orbiting Geophysical Observatories was to conduct diversified geophysical experiments to obtain a better understanding of the earth as a planet and to develop and operate a standardized observatory-type satellite.

OGO consisted of a main body, two solar panels, each with a solar-oriented experiment package (SOEP), two orbital plane experiment packages (OPEP) and six appendages, EP-1 through EP-6, supporting the boom experiment packages. The main body of the spacecraft was attitude controlled by means of horizon scanners and gas jets so that its orientation was maintained constant with respect to the earth and the sun. The solar panels rotated on a horizontal axis extending transversely through the main body of the spacecraft. The rotation of the panels was activated by sun sensors so that the panels received maximum sunlight. Seven experiments were mounted on the solar panels (the SOEP package). An additional axis, oriented vertically across the front of the main body, carried seven experiments (the OPEP package). Nominally, these sensors observed in a forward direction in the orbital plane of the satellite. The sensors could be rotated more than 90 deg relative to the nominal observing position and more than 90 deg between the upper and lower OPEP groups mounted on either end of this axis.

Atlas The Atlas rocket, originally developed as America's first ICBM, was the basis for most early American space exploration and was that country's most successful medium-lift commercial launch vehicle. It launched America's first astronaut into orbit; the first generations of spy satellites; the first lunar orbiters and landers; the first probes to Venus, Mars, Mercury, Jupiter, and Saturn; and was America's most successful commercial launcher of communications satellites. Its innovative stage-and-a-half and 'balloon tank' design provided the best dry-mass fraction of any launch vehicle ever built. It was retired in 2004 after 576 launches in a 47-year career. More...

Delta The Delta launch vehicle was America's longest-lived, most reliable, and lowest-cost space launch vehicle. Development began in 1955 and it continued in service in the 21st Century despite numerous candidate replacements. More...

Atlas The Atlas rocket, originally developed as America's first ICBM, was the basis for most early American space exploration and was that country's most successful medium-lift commercial launch vehicle. It launched America's first astronaut into orbit; the first generations of spy satellites; the first lunar orbiters and landers; the first probes to Venus, Mars, Mercury, Jupiter, and Saturn; and was America's most successful commercial launcher of communications satellites. Its innovative stage-and-a-half and 'balloon tank' design provided the best dry-mass fraction of any launch vehicle ever built. It was retired in 2004 after 576 launches in a 47-year career. More...

Delta American orbital launch vehicle. The Delta launch vehicle was America's longest-lived, most reliable, and lowest-cost space launch vehicle. Delta began as Thor, a crash December 1955 program to produce an intermediate range ballistic missile using existing components, which flew thirteen months after go-ahead. Fifteen months after that, a space launch version flew, using an existing upper stage. The addition of solid rocket boosters allowed the Thor core and Able/Delta upper stages to be stretched. Costs were kept down by using first and second-stage rocket engines surplus to the Apollo program in the 1970's. Continuous introduction of new 'existing' technology over the years resulted in an incredible evolution - the payload into a geosynchronous transfer orbit increasing from 68 kg in 1962 to 3810 kg by 2002. Delta survived innumerable attempts to kill the program and replace it with 'more rationale' alternatives. By 2008 nearly 1,000 boosters had flown over a fifty-year career, and cancellation was again announced. More...

Cape Canaveral America's largest launch center, used for all manned launches. Today only six of the 40 launch complexes built here remain in use. Located at or near Cape Canaveral are the Kennedy Space Center on Merritt Island, used by NASA for Saturn V and Space Shuttle launches; Patrick AFB on Cape Canaveral itself, operated the US Department of Defense and handling most other launches; the commercial Spaceport Florida; the air-launched launch vehicle and missile Drop Zone off Mayport, Florida, located at 29.00 N 79.00 W, and an offshore submarine-launched ballistic missile launch area. All of these take advantage of the extensive down-range tracking facilities that once extended from the Cape, through the Caribbean, South Atlantic, and to South Africa and the Indian Ocean. More...

Vandenberg Vandenberg Air Force Base is located on the Central Coast of California about 240 km northwest of Los Angeles. It is used for launches of unmanned government and commercial satellites into polar orbit and intercontinental ballistic missile test launches toward the Kwajalein Atoll. More...

Cape Canaveral LC12 Atlas launch complex. The complex was built for the Atlas ballistic missile program. Launch sites 11 to 14 were accepted between August 1957 and mid-April 1958. Complex 12 supported its first Atlas launch on 10 January 1958, and it supported nine Ranger missions and four Mariner missions between 12 August 1961 and 15 June 1967. Complexes 11, 12 and 14 were deactivated in 1967, and Complex 13 was deactivated in April 1978. More...

OGO 1 - .
Payload: OGO A. Mass: 487 kg (1,073 lb). Nation: USA. Agency: NASA Greenbelt. Class: Earth. Type: Magnetosphere satellite. Spacecraft: OGO. Decay Date: 1980-08-10 . USAF Sat Cat: 879 . COSPAR: 1964-054A. Apogee: 127,394 km (79,158 mi). Perigee: 21,446 km (13,325 mi). Inclination: 44.6000 deg. Period: 3,809.50 min. Two experiment booms failed to properly deploy, with one of the booms obscuring a horizon scanner's view of earth. As a result, the spacecraft attitude could not be earth oriented and OGO 1 remained spin stabilized at 5 rpm. Nevertheless, data from all 20 experiments on board was received, although at a 'less than expected capacity' from some of them. Twelve of the experiemnts were particle studies and two were magnetic field studies. In addition, there was one experiment for each of the following types of studies: interplanetary dust, VLF, Lyman-alpha, Gegenschein, atmospheric mass, and radio astronomy. During September 1964, acceptable data were received over 70% of the orbital path. By June 1969, data acquisition was limited to 10% of the orbital path. Spacecraft operation was restricted to Spring and Fall due to power supply limitations. There were 11 such 3-month periods prior to the spacecraft being put into stand-by mode on 25 November 1969. By April 1970 the spacecraft perigee had increased to 46,000 km and the inclination had increased to 58.8 deg. All support was terminated November 1, 1971.

OGO 2 - .
Payload: OGO C (S-50). Mass: 507 kg (1,117 lb). Nation: USA. Agency: NASA Greenbelt. Class: Earth. Type: Magnetosphere satellite. Spacecraft: OGO. Decay Date: 1981-09-17 . USAF Sat Cat: 1620 . COSPAR: 1965-081A. Apogee: 1,515 km (941 mi). Perigee: 419 km (260 mi). Inclination: 87.4000 deg. Period: 104.40 min. OGO 2 was a large observatory instrumented with 20 experiments designed to make simultaneous, correlative observations of aurora and airglow emissions, energetic particles, magnetic field variations, ionospheric properties, etc., especially over the polar areas. Soon after achieving orbit, difficulties in maintaining earth lock with horizon scanners caused exhaustion of attitude control gas by October 23, 1965, 10 days after launch. At this time, the spacecraft entered a spin mode (about 0.11 rpm) with a large coning angle about the previously vertical axis. Five experiments became useless when the satellite went into this spin mode. Six additional experiments were degraded by this loss of attitude control. By April 1966, both batteries had failed, so subsequent observations were limited to sunlit portions of the orbit. By December 1966, only eight experiments were operational, five of which were not degraded by the spin mode operation. By April 1967, the tape recorders had malfunctioned and only one third of the recorded data could be processed. Spacecraft power and periods of operational scheduling conflicts created six large data gaps so that data were observed on a total of about 306 days of the 2-yr, 18-day total span of observed satellite data to November 1, 1967. The spacecraft was shut down on November 1, 1967, with eight experiments still operational. It was reactivated for 2 weeks in February 1968 to operate the rubidium vapor magnetometer experiment.

OGO 4 - .
Payload: OGO D (NASA S-50A). Mass: 634 kg (1,397 lb). Nation: USA. Agency: NASA Greenbelt. Class: Earth. Type: Magnetosphere satellite. Spacecraft: OGO. Decay Date: 1972-08-16 . USAF Sat Cat: 2895 . COSPAR: 1967-073A. Apogee: 885 km (549 mi). Perigee: 422 km (262 mi). Inclination: 86.0000 deg. Period: 97.80 min. OGO 4 was a large observatory instrumented with experiments designed to study the interrelationships between the aurora and airglow emissions, energetic particle activity, geomagnetic field variation, ionospheric ionization and recombination, and atmospheric heating which take place during a period of increased solar activity. After the spacecraft achieved orbit and the experiments were deployed into an operating mode, an attitude control problem occurred. This condition was corrected by ground control procedures until complete failure of the tape recording systems in mid-January 1969. At that time, due to the difficulty of maintaining attitude control without the tape recorders, the attitude control system was commanded off, and the spacecraft was placed into a spin-stabilized mode about the axis which was previously maintained vertically. In this mode, seven of the remaining experiments were turned off since no meaningful data could be observed by them. On October 23, 1969, the satellite was turned off. It was reactivated again in January 1970 for 2 months to obtain VLF observations.

OGO 6 - .
Payload: OGO F. Mass: 634 kg (1,397 lb). Nation: USA. Agency: NASA Greenbelt. Class: Earth. Type: Magnetosphere satellite. Spacecraft: OGO. Decay Date: 1979-10-12 . USAF Sat Cat: 3986 . COSPAR: 1969-051A. Apogee: 1,089 km (676 mi). Perigee: 397 km (246 mi). Inclination: 82.0000 deg. Period: 99.70 min. OGO 6 was a large observatory instrumented with 26 experiments designed to study the various interrelationships between, and latitudinal distributions of, high-altitude atmospheric parameters during a period of increased solar activity. On June 22, 1969, the spacecraft potential dropped significantly during sunlight operation and remained so during subsequent sunlight operation. This unexplained shift affected seven experiments which made measurements dependent upon knowledge of the spacecraft plasma sheath. During October 1969, a string of solar cells failed, but the only effect of the decreased power was to cause two experiments to change their mode of operation. Also during October 1969, a combination of manual and automatic attitude control was initiated, which extended the control gas lifetime of the attitude control system. In August 1970, tape recorder (TR) no. 1 operation degraded, so all recorded data were subsequently taken with TR no. 2. By September 1970, power and equipment degradation left 14 experiments operating normally, 3 partially, and 9 off. From October 14, 1970, TR no. 2 was used only on Wednesdays (world days) to conserve power and extend TR operation. In June 1971, the number of 'on' experiments decreased from 13 to 7, and on June 28, 1971, the spacecraft was placed in a spin-stabilized mode about the yaw (Z) axis and turned off due to difficulties with spacecraft power. OGO 6 was turned on again from October 10, 1971, through March 1972, for operation of experiment 25 by The Radio Research Laboratory, Japan.